Once you click on sync messages all the conversation will get synced with your CRM. This button appears at the bottom of the conversation panel only if you have contact present in your CRM.
If you are on our professional or Enterprise plan we will auto-sync your conversations. However, if you are on our Basic plan then you would need to press on sync every time you send a new message.
Leadjet also offers our message template feature for all our users, you can check out how message sync and the template feature work in practice from here.