Period piece used to correct your text (12)
I believe the answer is:
spellchecker
'to correct your text' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'period piece' is the wordplay.
'period' becomes 'spell' (spell can mean a period of time).
'piece' becomes 'checker' (I can't explain this - if you can you should give a lot more credence to this answer).
'spell'+'checker'='SPELLCHECKER'
'used' acts as a link.
Can you help me to learn more?
(Other definitions for spellchecker that I've seen before include "Might one be confused by form from" , "Computer device which scrutinises text" , "Means of spotting misprints" , "Dumbledore, for example" .)