Select the cell or range containing the link
Right-click and choose Remove Hyperlink
Use Ctrl+K, then remove the address in the Link to field
Copy the cell and use Paste Special > Values
Select all linked cells and use Find and Replace to remove hyperlink text if needed
For multiple links, use the Review tab and check workbook links
Use Data > Edit Links to break external links
Open the Name Manager and delete linked named ranges if necessary
Remove formulas that reference external workbooks
Save the file after removing the links