Create a Google Doc and name the file
For example, if Bob Adrian Jones is meeting with Jen Tai Yin Lee, the title of the file would be
Use three letter initials when possible since there may be people with the same initials.
Share the file with the other person, using the Share option in the Google Doc.
Create a Direct Message channel in Mattermost and add the other person.
Add a link to the Google Doc at the top of the Direct Message channel by editing the header of the channel. Choose Edit Header and paste the link.
Use the file for 1-1s to post material in advance and to write notes of your discussions.