You have a link in your sig to looking for skilled web designers yet you don't know what DA is?
DA is the acronym for Domain Authority and PA is acronym for Page Authority. As the name suggest DA is domain authority meaning it based on how well your domain will appear in search engine rankings based on number of backlinks, Page Rank, Traffic, Mozrank, Moztrust and some more other metrics.
DA = Domain Authority
PA = Page Authority
PR = Page Rank
You can find many DA/PA/PR checkers online.
Just do a Google search for "DA PA PR Checker".
I like to use Website Authority Checker - PageRank, DA, PA MOZ