There are many sites that provide codes for hex colours. Just listing a few that you might like.
https://www.color-hex.com/color-names.html
https://htmlcolorcodes.com/color-picker/
https://www.colorhexa.com/color-names
Copy the code starting with #. Highlight the text or link that you'd like to appear in that colour, then click on the drop icon. Then is a small space below the colours for you to enter the hex colour code. And next to it is a blue box which is the OK button. Click on that and your desired part should appear in the colour of your choice. You can also edit a body of text you previously posted and add colours in the same way.