Hi awesomechase
Thank you for your post.
To be able to add a Ship Date, you will need to customise an invoice. Go to Setup >> Customise forms >> Invoices >> Choose which applies to you and click on Customise button >> Once it has opened the form, click Fields at the top >> Search for Ship Date. There is also a report available by going to Reports at the bottom part of the dashboard >> Sales >> To Do List >> To Do List - Orders To Be Shipped. Here are some Help Articles that you can use as a guide.
Please feel free to post again. I'm happy to assist further.
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