Typically, when companies do an Initial Public Offering (IPO) and list on a stock exchange for the first time (go public) all outstanding shares would convert to the new public class of share. All common shares would convert into the new common share class, and all preferred shares would convert to the new preferred share class, or being converted at a set rate into common shares.
Existing shareholders would also sometimes be limited for a certain number of days before they could sell their shares in the market.
The decisions around how to treat existing outstanding shares are decided by company management and the underwriting investment bank at the time of the IPO.
Issuing shares as part of an equity crowdfunding round would not negatively affect this process.