How to 'linkify' plain text URLs (locally) on the Mac?
To convert multiple plain text URLs to hyperlinks in a rich text file in TextEdit, you must apply an action.

After pasting the text, go to Edit > Substitutions > Show Substitutions, making sure 'Smart Links' is ticked, and either select the text and use 'Replace in Selection' or use 'Replace All' to apply to whole document itself:



EXAMPLE:

I pasted same text twice for demonstration.

After pasting I selected the second paragraph (only for demonstration) and used the Smart Links - Replace in Selection: