Yes, the company would need to file an S-1 or S-3 to register the shares. Some exemptions may be used to sell before registration but only in limited amounts. Rule 144 is an exemption that may be used to sell restricted securities if the holder meets certain criteria.
If the holder is not an affiliate of the company (director, officer, or large shareholder) then he/she can sell restricted securities through rule 144 without volume restrictions if:
1) the securities have been held for more than 6 months and
2) the company is current in its financial reporting