Youtube is very big platform for watching videos and uploading videos.Youtube is from.google.There is no way to download official youtube app for pc like windows or mac os but don't worry ;there is simple trick that you can use full fledged youtube app in widows and mac os that is web app option in chrome ,microsoft edge.
Steps to follow in chrome and edge
Step 1. Go to chrome
Step 2.Go to www.youtube.com
Step 3.There will be (+) option .Click on the (+) option
Step 4.Then simply click install button
Now your youtube web app is installed ,you can simply use as normal app

Steps to follow in firefox browser
Step 1. Go to firefox browser
Step 2.Go to www.youtube.com
Step 3. There is add to homscreen option (atohs)
Step 4.Simply click install button
Now your youtube web app is installed ,yoy can simply use as normal app