how do i download catalina

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.

macOS Catalina 10.15 hardware requirements It this computer listed as Qualifying for Catalina ?

macOS Mojave 10.14 hardware requirements

Make Time Machine Backup  is very useful and can be used to Revert to Previous Working macOS

Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Catalina, Big Sur & Monterey 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 required update or upGrades to 64 Bit Versions.

Back up your data, check your applications for compatibility, click here, and if your Mac is a 2012 or newer model(2013 for desktop Mac Pros) and didn't ship with Big Sur or newer, then on the download link for Catalina.

Catalina and newer won't run 32-bit software; download and use Go64 to scan for it. To look other programs up, click here.

(218094)