Import Data into CRM for Prospecting?

I'm helping get a business off the ground and am doing some prospecting for the new business. I'm doing most of the prospecting on Sales Navigator which keeps me on the platform for messaging without any integration into the CRM.

How are companies getting data on prospective customers into the CRM? (I'm not interested in buying lists.) Having the data in the CRM would give me better workflow and tracking, not to mention using CRM messaging capabilities.

Apollo might be a (clunky) option for this, but clunky is better than manual.

Any ideas on bridging the gap between finding prospects and tracking/managing pursuits in a CRM?

If it matters, my CRM is the free sales option on HubSpot.