[AnotherCat]

This may differ a bit due to app's own handling and the OEM's version of Android. But in near stock versions of Android (e.g. one Android One phones such as those of Nokia and Google) when one touches the option in an app to select a folder to store in it takes one to a near empty display with "SELECT" down in the bottom right corner and among a few other things a menu hamburger at the top left corner. Touch that menu hamburger and one gets a drop down which includes the phone's internal storage and external storage (SD Card).

Select the SD Card and one gets a drop down of all the folders on the card, touch the one you want (or the subfolder within that iof one wants the subfolder, then touch SELECT down in the bottom right corner of the display.

OEM versions of Android should be basically the same, for example without checking I recall my Samsung tablets are very much the same. I am the first to agree that the process is not intuitive for the first time doing it (I think because one is tempted by the "SELECT" option to select something from a blank screen before one touches the hamburger to get the things to select).

EDIT: the above is for cards designated as portable storage or similar term, if ones card has been user designated as internal storage the procedure above may be a little different but touching the menu hamburger should get one on the way to listing the available folders - I can't comment further as I never use cards designated as internal storage (in fact many devices will not allow them to be so).