If you, as an admin, want to update the number of points for a selection of members or all members at once, you can easily do this via the Members section in the backend.

If you go to Members, you can 1) apply a filter to select a specific audience, then hit the checkbox and choose what you want to do:

You can edit the members you selected, or 2) select all members matching your filter and click edit.

Here you can choose points or lifetime points and select if you want to add, remove, or set the total of points for all selected members to the same value. Don't forget to click apply.