Use YouTube Premium for offline viewing in the YouTube app
Use the official YouTube app’s download feature where available
Check whether the video owner has enabled downloads
Use a browser extension or third-party downloader only if you have permission and it complies with local laws and YouTube’s terms
Paste the video URL into a downloader tool if you are authorized to do so
Select the desired format and quality
Download the file to your device
Scan downloaded files with antivirus software before opening them