Calendar with week numbers

Hi, I work as a project manager and at the end of every other week I have to submit an interim report on the project to the management and clients of the project. I've had a few instances where I've gotten confused with the week numbers. Is there a calendar where I can see what week of the month it is on the invoice?

What does the company do? Isn't it marketing? I'm a concert manager and I know that you have to actively promote a concert four weeks in advance. To avoid confusion, I count the weeks here https://timesles.com/en/calendar/weeks/days/today/ . For me everything is simple and clear here, I usually use several calendars here, for example a calendar with working days, a calendar with days off and a calendar with holidays. Maybe you can recommend a better alternative?