Some people "block" a quilt to help square it up. IMHO squaring up and blocking are really only necessary if the quilt is to be hung in a show or on a wall. Rarely will you notice a slightly out of square quilt laying on the bed and you will never notice it if it is in a perpetual state of being snuggled in.
Here are a few links for blocking and squaring up after quilting and before binding
http://www.kimmyquilt.com/article/blockingaquilt/
https://www.leahday.com/art-blockingquilt/
https://cowtownquilts.wordpress.com/...block-a-quilt/
Just google how to block a quilt and you will get loads of hits.