This does not show up when trying to add to a character's items list

I don't see where I can add these to my characters inventory'

I belive these are 25 gp each

Still can’t add these to my character’s inventory :(

search "Arrows"  and the option for +1, +2, +3 arrows will come up

Nope. Nothing shows up when you enter "arrows" or "arrow". 

https://imgur.com/a/MyEuue3

what source books do you have unlocked in DnDBeyond?

Do these stack with a magic bow?

That's my question as well.

yes

Agreed.  I never came back and answered/removed my question.  My understanding, from Sage Advice and other commentary, is that *EACH* piece of magical ammunition is unique, and "a consumable".  So yes, your +1 arrow in your +1 bow gives a total +2 to hit and damage... and then that "Uncommon Consumable" is gone forever.  Since "consumables" are half the price of permanent magic items (according to Xanathar), that means for every two "Arrows +1", you could have had another +1 weapon in the party.

Would this stack with a + 1 bow?

So a +1 bow and +1 arrows be a total of plus 2?