How do I update my iMac to macOS 11 Big Sur?

Hi, Byulady- it’s easy, check the requirements for MacOS 11.0.1 and if your iMac meets those requirements, go get it from the App Store

here’s a link to the requirements :

macOS Big Sur - Technical Specifications

i don’t know what year of iMac 27” you have, just that you have one, so can’t say if it’s able to run Big Sur or not.

John B

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install.  For Best results use Safari to commence the download as Others may not work.

Safari will open a redirect and open the Apple Store where the download can commence.

Does this computer appear as Listed and qualifying for an upGrade to a newer version of macOS? 

The below links will help identify which version of macOS  this computer may Qualify to run.

macOS Big Sur 11 hardware requirements

FYI - The Only Version available from the Apple Apps Store is the most recent version Big Sur 11.7.5 and Not version 11.0.1

Make Time Machine Backup  is very useful 

Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Catalina, Big Sur, Monterey, Ventura supports only 64 bit and there is no workaround.

Suggest using Go64 to find 32 bit application before attempting the upGrade. Some or many of the Application already installed may require an update or upGrades to 64 Bit Version

1. Mac's run macOS, iPhones and iPads run iOS.
2. macOS versions are determined by the year model.

What year model is your iMac?

see > Identify your iMac model - Apple Support