On your 2018 federal tax return, you can claim any new
eligible tuition fees for 2018, as well as any tuition that you have carried
forward from previous years. On your provincial return it would depend on which
province you are in, as some provinces no longer have the tuition credit.
If you didn’t claim your tuition from previous
years on tax returns for those years, you will have to adjust your returns for
those years to get the carry forward amount. Here is how you can make changes
after you have filed your tax return through the CRA or through ReFILE: https://turbotax.community.intuit.ca/replies/2647992