Export all data for Contact
Welcome to stack exchange. There are some other questions that may provide you with some answers. Before asking a question you should always do a search. Try searching for "export all data". Also it would be worth saying why you want to do this export. It seems an odd thing to do with a new site.

But to help you, "Export PRIMARY contact fields" is a particular set of fields chosen by someone else and rather general. If you choose "select fields for export, you can chose whatever you want. A bit tedious for all fields, but you can save the selection for later use.

Be aware that you can't export multi-value custom fields this way (though you can get a report to do this.