You cannot change invoice layout.

You can only change the following (Invoicing Settings Invoice groups

• Logo
• Stamp
• Corporate data
• Postscript displayed on bottom of invoice

In Invoicing Settings General, you can also disable displaying some values on invoice:

• dont_show_bank_information – account number, bank name, IBAN and BIC
• dont_show_ss – specific symbol
• dont_show_vs – variable symbol