Convert PHP basic invoice form to Insert Into MySQL Database

As you can see in the title above, I have 2 PHP form where I need it to be functional. Both must have abilities to save form data in Mysql database into multiple table. Example : 1. Client data into client table 2. Invoice details (multiple row) into client invoice table. When we retrieve back client information , it will automatically call back invoice detail. It will need Unique client ID I believe. That not all, one of my form need some simple programming where 1. user have abilities to add / remove row field. Yes it is invoice. 2. Automatic calculate Tax, Total Amount, Grand Total and a few more calculation Overall: Both have calculation. 1 of the form already have calculation but need some adjustment because it appears in plain text instead of form fields. Both need to be save in database. Feel free to bid. Thank you :D