If your organisation needs to be on many social networks at once, there are paid social management services which include support for Mastodon such as Buffer at https://buffer.com/mastodon and Publer at https://publer.com
However, if you just want to schedule your Mastodon posts you don't need to use commercial services. Mastodon has its own built-in free open scheduling system available through third party apps (more info at https://fedi.tips/scheduling-posts-on-mastodon).
