Copy text(block) into Vim form external file
You can follow these two methods:

Method 1. Shift + Ins

First, please make sure to turn off the Num Lock in order your Ins button to work as expected

1. copy the content of the text from the text file (Ctrl-C or right-click & copy)
2. open the file you want to edit with the vim editor
3. type ‘i’ to enter the insert mode ( check at the bottom for — INSERT –)
4. hit this key combination: Shift + Ins

Method 2. Shift + Right-Click & Paste

1. copy the content of the text from the text file (Ctrl-C or right-click & copy)
2. open the file you want to edit with the vim editor
3. type ‘i’ to enter the insert mode ( check at the bottom for — INSERT –)
4. hit this key combination: Shift + Right-click & choose the ‘Paste’ from the menu

see: https://techexplorations.com/blog/kicad/blog-how-to-copy-text-into-vim/

If you are copying text for which the formatting should not change, beware that the above process can introduce changes to the formatting. For example, if you are copying Python code into a file using Vim, be prepared for the indentation to be altered, and therefore your program to not work as expected. In Python, code blocks like loops are denoted using text indentation.

To avoid this from happening, you can use Vim’s paste mode. When you enable paste mode, Vim will not auto-indent any text that you paste. To enable paste mode, follow this process: