Yes, but you cannot install it over Big Sur. If you download the installer on a newer Mac, it will warn you that you cannot install the older OS. You would typically download this file to create a bootable installer for an older Mac machine.
⚠️ Avoid third-party sites claiming to have “DMG files” for Catalina. They often contain malware. Always use Apple’s official links or the softwareupdate terminal command. download os catalina 10.15.7
: Minimum 4GB of RAM (8GB or more is recommended for better performance). Yes, but you cannot install it over Big Sur
Run the installer directly or restart with Option key → select the USB drive. download os catalina 10.15.7