Make law -- stick up document finally (5)
I believe the answer is:
enact
'make law' is the definition.
(I've seen this before)
'stick up document finally' is the wordplay.
'stick' becomes 'cane' (cane is a kind of stick).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'finally' indicates one should take the final letters.
The last letter of 'document' is 't'.
'cane' written backwards gives 'enac'.
'enac'+'t'='ENACT'
(Other definitions for enact that I've seen before include "get into law" , "Pass into law" , "Authorize" , "Decree" , "Play one's part" .)