Combine two excel spreadsheets

HI there, Currently when filling out pay reports for my employees I have ONE sheet where I input figures from my week and ANOTHER sheet where I fill out invoices for my staff. This means a lot of back and forth between the two sheets. I would like someone to combine the two so that when a person is entered in as working on ONE day their name and amount they sold is automatically added to the invoice, meaning I only have to enter numbers and dates once I know my budget isn't much but I hope that someone who possesses this knowledge will see this as a few minutes work and I promise I'll be needing services in future.