https://www.matthewdevaney.com/powerapps-collections-cookbook/

Create a form with a few Input fields:

Test it add a few data.
To view summited data go: View -> Collections
or insert a galley

Edit the Gallery to your needs:

Clear the collection:

add button, and onSelect = Clear(ContactInfo)

Delete one Item – ThisItem

Select a record and insert a trash can icon

Add onSelect: Remove(ContactInfo, ThisItem)

Item Detail

Add the labels and input fields, than for each Default input field show the selected Item.

Set fields to View only.

Group Display field and change the Display Mode to View

Add an icon Edit and set a variable to tangle true or false

Set(varEdit, !varEdit)

Now go back to Group Display mode and change it to check on varEdit

To Update use Patch

Patch use a datasource = ContactInfo,
which record = Gallery1.Selected
and the inputs

Patch(ContactInfo, Gallery1.Selected, {Name: I_Nama_det.Text, Phone: I_Phone_Det.Text, Comments: I_Comments_des.Text})

Collect specific columns in a SP List in a Collection

ClearCollect(myNewCollection,ShowColumns(myDataSource,”Column1″,”Column2″))