Handling and storing values on global variables while running several macros

Hello!

I'm using a workbook that runs 15 macros which create 18 sheets of information based on 1 sheet of raw data. At the moment, the user has to input requested values that are used for the macro that is currently running, but many of these values are repeated and all of them could be entered at the beginning, upon launching the first macro, because they all refer to locations of the data fields from the first sheet of raw data. So I'm thinking that I should stop using local variables and store them for all the macros to use, and clear them only once all of them have run. The question is how do I define global variables and where should I place the code where the values for these are entered?

Thanks in advance.