Tor: Can I run a Tor relay?

Short answer

Yes, volunteers operate the relays that carry Tor traffic. Decide whether you can support a non-exit relay, bridge, or exit relay, then read the current Tor Project operator guidance for bandwidth, memory, hosting rules, and maintenance. A bridge or Snowflake proxy may fit better when you have limited resources or do not want a public relay listing.

Sources

Tor Project: Relay requirements, Tor Project: Relay types.