How can I manually add a password to Chrome password manager?

If you want to save a password from a page where there is no password input field, you can simply add a password input field anywhere on the page and start writing into that field. Google Chrome then adds a small key icon into the navigation bar which allows you to store the password onto that domain.

How to add a password-input field into the page with the Chrome DevTools

1. Go to your desired web site.
2. Hit F12 on your keyboard to open the Google Chrome DevTools or right click on an element and click on Inspect.
3. Select the tab Elements.
4. Select any (small) HTML tag and hit F2 to edit it (or double-click).
5. Append the following element: <input type="password">.
6. Click on another HTML tag to save it.
7. Enter some password into the newly created input field on the website.

At the moment there is a beta-feature which can be activated on the following chrome settings page: chrome://flags/#password-import-export

It can be used to import a list of passwords.

Furthermore, I found this solution also on another question.