Tap the plus icon (+) and allow permissions to access files and photos. Choose your desired file(s), then tap Done.

1) In the top right, tap the plus icon (+).

2) Tap Upload.

3) Tap Photos and Videos to upload files from your device's Photos app. Otherwise, tap Browse to look in additional locations from which to upload.

4) If you are prrompted with Allowing permissions, select the appropriate option. If you click Don't Allow, you cannot upload files or photos.

5) Tap the items you wish to upload. Then, tap Done.

Outcome

You have uploaded files from your iPhone or iPad to OneDrive for Business.