How do I increase memory storage to update my Macbook Pro?

If you are having troubles updating because you are running out of storage on the Mac Pro try the following steps:

• Delete media like movies, music, and podcasts
• Delete files in the Downloads folder
• Erase junk mail from the Mail app
• Delete program installer file for program already installed on the device
• Empty trash bin
• Restart device

once a Mac is no longer eligible for macOS upgrades, hardware upgrades will not make it eligible for further macOS upgrades.

if that is not what you are asking, please read Writing an effective Apple Support Communities Question and come back with more details.