1. Open the folder containing Outlook signatures by pasting below folder path into the Address box in a folder and pressing the Enter key.
Folder path of Outlook signatures: %AppData%\Microsoft\Signatures

2. Open the folder where the downloaded HTML signatures are saved, select all folders and files about the HTML signatures, right click and select Copy from the right-clicking menu. See screenshot below:
Note: You can also copy these folders and files with selecting all and pressing the Ctrl + C keys simultaneously.

3. Now return to the folder containing Outlook signatures, and then paste HTML signatures with pressing the Ctrl + V keys simultaneously.

4. Show file name extensions in the folder with checking the File name extensions option on the View tab in Windows 10 or Windows 8. See screenshot:

Note: If you are working in Windows 7, please display the file name extensions as follows: (1) Click Organize > Folder and search options; (2) In the Folder Options dialog box, go to View tab, uncheck the Hide extensions for known file types option, and (3) click the OK button. See screenshot:

5. Find out the HTML file of one downloaded signature, click into its name, change its extension from html to htm, and press the Enter key. See screenshot:

6. In the opening Rename dialog box, please click the Yes button to go ahead.

Note: If there are several downloaded HTML signatures, please change their extensions to htm with above Step 5-6 one by one.

So far you have imported the HTML signatures into your Outlook. For adjusting/changing the signatures, please go ahead with below steps:

7. Create a new email with click Home > New Email in the Mail view in Outlook, and then click Insert > Signature > Signatures in the new Message window. See screenshot:

8. In the popping out Signatures and Stationery dialog box, please (see screenshot below):

(1) In the Select signature to edit section, please click one of imported signatures you will edit;
(2) Edit the signature as you need in the Edit signature section. Note: Please repeat above (1) and (2) to edit other imported signatures one by one.
(3) Click the OK button.

9. Now you have edited the imported HTML signatures as you need. Please close the new Message window.

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