This note is based on the standard web interface for Mastodon
Depending on the screen size you are using to access Mastodon on the web, the new posting window will already be displayed or you may have to click on the Publish button at the top.
1 This is the area to type your text for your post. As you type, the counter 4 will start to decrease.
Clicking on 2 will show a list of available emojis. In addition to the typical set, your server admin may have added custom emojis. If you use these, a copy will be sent to the recipient's server automatically to ensure they can see your emoji.
When you are ready to publish your post, click 5. Your post will immediately be processed by your server and distributed out onto the Fediverse. It will also appear in your own Timeline.
If you cannot click Publish, you have exceeded your maximum post size – check 4 is not a minus figure in red.
You can paste or type web address into 1. Each will take up 13 characters of your post limit. Do not use web shortening services.
If you wish to refer to someone in your post, type their fediverse address as part of 1. It must start with an @ sign. As you type, you may be offered a list of suggestions from your server. If the person is not listed just keep typing. An example of a mention could be: Hi @fred@blogs.social, how are you today
The area marked 3 above provides additional options before you Publish.