Do you want to schedule your posts on Mastodon so that you write them now and they are automatically published later?
Some third party apps including Tusky and Fedilab have a built-in scheduling option. Fedilab also runs a website at https://plan.fedilab.app which lets you schedule posts.
If you want a professional scheduled post management system, there are third party commercial services such as https://publer.io and https://buffer.com that now include Mastodon compatibility.
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