If you're using Webex App for web, you won't be able to edit messages, but you can see when messages have been edited.

You can edit messages with attachments, except for messages that have audio file attachments.

Hover over your message and click Edit message. Then, make your changes and click Update.

After you update the message, you'll see (Edited) next to it in the space. You can only edit a message 10 times.

You can use the shift + up arrow shortcut to edit the last message you sent in a space.

Long press your message, and tap Edit, make your changes and then tap to send.

You'll see a note next to the message in the space, to indicate that it’s been edited.

Hover over your message and click Edit message. Then, make your changes and click Update.

After you update the message, you'll see Edited next to it in the space. You can only edit a message 10 times.

You can't edit messages that have attachments, screen captures, or GIFs.