Give some thought into your quest to move apps from her tablet's internal storage to a microSD card -- keep in mind this is not an optimal solution to add storage capacity, it is a workaround kluge. Current microSD cards are quite robust now and adequate as cursory storage media, but she's better off having more internal storage memory to begin with. If upgrading to a tablet with more internal storage isn't viable however, using a microSD card does involve some compromises
-- microSD cards are faster now but still not as quick as just relying upon internal storage, so basic reading and writing of data (mostly writing) is always just a little bit faster when it involves the internal storage. Yes it's just milliseconds in difference but this applies to everything -- interactions between the operating system and apps, copying/moving/deleting files, etc. -- so depending what she may or may not be actively doing there 'could' be some lag on occasion.
-- some but not all apps will be able to be 'moved' to the card. A better, more accurate term will be 'split' Some apps have to be left as is, requiring only internal storage. Those apps that you can 'move' are actually divided with part staying within internal storage and part on the card. So yes you free up some storage space in the internal storage but at that point it's now a matter where she has to leave that microSD card always within her tablet. If she does use the card to manually transfer files and things to her computer/laptop or her phone, once she pulls the card out that creates a situation where those split apps are now unable to function properly until the card is back in place.
But those caveats may or may not even apply depending on how she's using her tablet. And that's the thing, we all use our mobile devices differently to do different things. For the most part though, evaluate just how much impact 'moving' apps will help. Unless she has installed a really sizable number of apps, even the total amount of apps themselves may not account for a significant amount of storage space. You really need to look in the Storage menu in her Settings menu and focus on what content is taking up a lot of storage and what needs to be left as is.
Just making idle assumptions, there's going to be a lot of saved photos, videos, and music files. Those will typically take up a lot of storage space, especially in aggregate. Especially video content, if she has a high res (i.e. 4K) video file of a movie saved, that itself could use 2 or 3 GBs of space (lower res videos are still sizable but not as much) Use the 'My Files' file manager app to move or delete files and folders. (Samsung includes that handy, but basic file manager with its devices).
Regarding deleting whatever apps she doesn't need or use, that's going to be a conditional matter. Apps she's installed will be removable, but there are going to be a number of apps that came pre-installed by Samsung that won't be Uninstallable by you.