adding brushes from free brushy to my iMac computer using Photoshop Elements 2021

Hello @defaultgx62sal1e8cb,

Please navigate to Applications > Adobe Photoshop Elements 2021 > Support Files > Presets > brushes and add the .abr file of the desired brush to this folder. When you launch Photoshop Elements, these brushes should begin to show up in the application.

Regards,

Medha

The location for brushes on my windows computer, using PSE 2021 (Adobe calls it 19, PSE 2020 was 18):

C:\Users\User\AppData\Roaming\Adobe\Photoshop Elements\19.0\Presets\Brushes

In MACS:

The application data folder on Mac, like some other operating systems, is hidden. So to navigate to it in the normal way, you need to show the hidden files in the Finder. Press Command + Shift + 

It says user after Users because I never named my account- what's important  is that you locate the appdata \ roaming directory.  

In windows there is a APPDATA LOCAL folder, and an APPDATA ROAMING folder.  You need to locate the MAC equivilant of the AAPP DATA ROAMING folder. 

When I download a brush file (an .ABR file)  I just drag it into my quick linked brush folder. 

I know nothing about Macs so I can't help you with your main question.  But I can tell you that Elements 2021 is actually Version 19 (not 2019).