Q2A SSO use WP user and WordPress by default doesn't allows to upload user avatar but your user can use gravatar and if they have already it will automatically appear.
If you want to allow your user to change avatar than you may need to install plugin in WordPress with allows your user to upload avatar.
some of are here
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.
April 20, 2021: Q2A 1.8.6 released!