You don’t need to be everywhere — you need a couple of well-kept, organization-owned accounts. For most small US charities, a Facebook Page and a LinkedIn Page cover donor trust and credibility; add Instagram if your work is visual.
Create each account under an organization email you control (not a personal login), and add a second admin so access never depends on one person. Use the same name, logo, and link everywhere so supporters can verify they’ve found the real you.
FFC can help connect your accounts during onboarding. Fuller platform-by-platform setup steps are forthcoming.