Hi, that’s a good question, with lots of different possibilities, I have a few general pointers, I’m sure you’ll get more responses possibly around Teams etc.
I’d first take a step back, look at the data, what state is it in, it’s a great opportunity to optimise and better arrange the contents as you move to the cloud. You can take a ‘lift and shift’ approach and migrate everything, or have a data cleanse, for example looking at old data, unmanaged data, how much of that should be migrated, if any of it. Dumping everything from a file server onto SharePoint is usually not the best approach but it does happen, you can also rearrange the data once it’s on the cloud but that’s not without it’s difficulties either. Also what about home folders and migrating them to OneDrive for Business, that’s another possible consideration to plan for.
The preferred way to arrange contents in SharePoint is with sites (site collections), for every unit of work create a site. Each site has a document library/shared library, which is where the documents live. You add members to the site and that’s grants access to the data, users can then sync the document library using OneDrive, where the contents can be easily accessed as if it was a drive.
This guide has some more specifics, this is using Microsoft’s free SharePoint Migration Tool (SPMT). This covers lots of the things to look out for and that should be done upfront like mentioned in the Access and remediate your content section as well as the overall planning.
https://docs.microsoft.com/en-us/sharepointmigration/fileshare-to-odsp-migration-guide
There are other options that are covered here for example Migration Manager:
https://docs.microsoft.com/en-us/sharepointmigration/migrate-to-sharepoint-online
I hope some of that helps!
