Exhibit 99.8

USER GUIDE –VIRTUALMEETING PLEASE READ CAREFULLY To start To participate online This year’s annual and special meeting of shareholders of 1. Make sure the browser on your device is compatible. Thomson Reuters Corporation will be held virtually on You will need the latest version of Chrome, Safari, Edge, Wednesday, June 14, 2023, at 12:00 p.m. (Eastern Daylight or Firefox. Internet Explorer is not supported. Time). You will be able to participate online using your Caution: Internal network security protocols including firewalls smartphone, tablet or computer. and VPN connections may block access to the Lumi platform for your meeting. If you are experiencing any difficulty By participating online, you will be able to view a live audio connecting to the meeting, ensure your VPN setting is disabled webcast of the meeting, submit or ask questions during the or use a computer on a network not restricted to security meeting and vote in real time, provided that you are settings of your organization. connected to the Internet. Questions may be typed or asked 2. Non-registered shareholders who wish to appoint by phone (as described on the next page). themselves as proxyholder and non-As usual, you may also provide voting instructions before registered/registered shareholders who wish to appoint another person as proxyholder MUST register the meeting by completing the proxy or voting information the proxyholder at form that has been provided to you. Please refer to the www.computershare.com/ThomsonReuters. Failure to “Voting Information and How to Attend” section of the do so will result in the appointee not receiving a circular for further details. username that’s required to submit or ask questions or vote at the meeting. Important Notice for Non-Registered Holders Using your smartphone, tablet or computer, go to the following address: Non-registered holders (being shareholders who hold their Meeting Access shares through a broker, investment dealer, bank, trust company, custodian, nominee or other intermediary) who www.tr.com/agm2023 have not duly appointed themselves as a proxyholder may virtually attend as guests but will not be able to vote or You will need the following information to log in: submit or ask questions during the meeting. Meeting ID Password If you are a non-registered holder and wish to attend, 451-573-659 tri2023 submit or ask questions and vote at the meeting, you should carefully follow the instructions set out on your Registered Shareholders voting information form and in the circular in order to appoint and register yourself as a proxyholder. If you are a The control number listed on your form of proxy. non-registered shareholder located in the United States, you also need to obtain a valid legal proxy from your Appointed Proxyholder intermediary. Please see the “Voting Information and How to Attend” section of the circular for details. The control number or username provided by the transfer agent. Registered Shareholders and Appointed Proxyholder: Registered Shareholders Select “I have a login”. Enter the control number listed on your form of proxy or Guests: Select “I am a guest” and fill in the form. e-mail notification as your username and the password above. You will be able to log into the site from 11:00 a.m. Appointed Proxyholder (Eastern Daylight Time) on June 14, 2023. We Enter the control number or username provided by the recommend that you log in at least 15 minutes before transfer agent, provided your appointment has been the meeting starts at 12:00 p.m. (Eastern Daylight Time). registered, and the password above.

To watch the live audio meeting, press on the broadcast icon. On a computer, the broadcast will appear automatically at the right side once the meeting has started. Once logged in, you will see the home page, where you can access the meeting information, documents and the audio broadcast. Voting Questions Once voting has opened, the voting tab will appear. Only registered shareholders or appointed The resolutions and voting choices will be displayed proxyholders may ask questions during the meeting. in that tab. To vote, select one of To ask a question, select the messaging tab. the voting options. Type your question within the box at the top Your choice will be of the screen and click the send arrow. highlighted. To ask a question verbally instead, send your phone A confirmation number and subject in the messaging tab. The Lumi message will also platform will dial you in the conference. Please mute appear to show your your computer and listen to the meeting on your vote has been phone only. This will prevent any delay or feedback received. from occurring. When called upon to ask your question, you will be unmuted. The items of business Questions sent via the Lumi AGM online platform for which you have will be moderated before being sent to the voted, or not yet voted, Chairman. is displayed at the top of the screen. You can change your votes until the end the voting period by simply selecting another choice. If you wish to cancel your vote, please press Cancel. You will continue to hear the meeting proceedings. To return to the broadcast tab on mobile, tap on the broadcast button after having voted. Please ensure that you are connected to the Internet at all times to be able to vote. If you are not connected, your vote will not be recorded. It is your responsibility to ensure you stay connected for the duration of the meeting. www.lumiglobal.com