I built a report off of the Constituent Summary report and I am wondering is there a way to include groups and tags in that report that will export as a csv? Also why are some reports only exportable as a pdf and others give the option as a csv?
Those fields aren't available from reports as far as I can see, but you can get your csv from a search. You can get all records from a contact search and then export including the group and tag fields. Or if you only want to select the records with groups or tags set you can use Search Builder to select these using include contacts where group is not empty and also include records where tag is not empty.