I have a VBA project I am doing in excel. I will have many workbooks that will use the same code and I do not want to have to copy the code to all the workbooks if I make a change. Is there anyway to have the code in one central place and then have all the workbooks access that code?
Yes, you have two options
1) Copy and paste the code in the Personal workbook.
More details here
Topic: Deploy your Excel macros from a central file
2) Create an Add-In
Mode details here
Topic: Creating An XLA Add-In For Excel
Note: You can create Add-In in VBA as well as Visual Studio. For COM Add-Ins (created using Visual Studio), please refer to this link.
Topic: Office Development with Visual Studio (VSTO)