Snap the receipt; the amount, supplier, category and date are read for you and counted in the right tax year.

Tap Money, then Add expense. You can type it by hand, or let the photo do it.
Tap Scan receipt and take a photo or pick one. The first time, the app asks whether it may send the photo to be read; only the photo goes, and it is not kept.
A sheet shows the amount, the supplier, a category and the date. Everything is a suggestion: change anything that is wrong, then tap Use these details. Nothing is saved without you seeing it first.
Tap Save expense. It joins the year's expenses on the Money screen, with the receipt attached, so Self Assessment is a list, not a shoebox. Kit, PPE, travel, training and insurance are the categories most rope access techs use.
Related: your first invoice, CIS for rope access, CIS calculator.