When clicking "invest" in a campaign, you show your interest in investing in the company running a crowdfunding campaign. The actual monetary transaction takes place outside of the platform, after the campaign has reached 100% of its minimum funding goal. Only then will payment instructions be issued to all investors.
You commit to the investment at that stage by signing a shareholder agreement.
Additionally, you should share the news of this company with your network! Help the campaign succeed by getting your like-minded friends and network involved as investors!