Tag Tip: You can import tags by making a column with a header called Tag and add your tags in each cell, separated by a comma. 

Important note for people that use Keap

It took me a very long time to realize that the phone field from the csv export in keap is not compatible with GHL. The parenthesis and dashes somehow jack it all up. I had to highlight the entire comumn in the cvs file and make sure it was number in, then replace the ( symbol with nothing, and the ) with nothing, and then I could import without messing up the data in GHL.