Back-and-forth emails just to agree a time for a site visit — there has to be a better way

the amount of time i waste on back and forth emails just to pin down a time for a site visit is genuinely embarrassing. i know tools exist for this. i just haven't got round to committing to one and that's entirely on me. what's the most painless way to let clients self-schedule a time without it requiring them to create an account or learn something new?