Want same invoice format
That format includes variables that Manager does not include in its sales invoices. So you will not be able to duplicate it, even with an extremely complex custom theme.
It could be done with some custom fields per invoice, and per line items.
Even with above it would require a lot and lot of heavy customization in custom theme. If you are not into HTML/CSS/Liquid you better speak with some programmer.
Do you have any reference?
The definitive reference on Liquid is linked in this Guide: https://www.manager.io/guides/10368.