Company registration is handled online by the Rwanda Development Board and is free of charge. You choose a legal form — most small ventures register as a domestic company limited by shares or as an enterprise — and reserve a name.
Registration issues a TIN automatically, so the next steps are opening a bank account, registering employees with RSSB, and applying for any sector licence you need (food, transport, tourism, finance, and construction all have specific regulators).
Plan for compliance from day one: monthly or quarterly tax filings, RSSB contributions, and trading licence payments to your district. Keeping clean books from the first month makes credit and tenders far easier later.