This feature is only available if you have Gutenberg enabled. It allows you to enable a dropcap and also Salal has a setting to change the colour of it.
Adding a Drop Cap
Although you can add a dropcap anywhere, they are generally added to the first paragraph of an article.
With the post editor open and you already have a paragraph created, look at the right column for the “Drop Cap” setting and toggle it on. Make sure you have the paragraph block active by clicking inside of it.
Change the Drop Cap Colour
Gutenberg does not have an option for colourizing your drop cap letter, so we added one for you.
Go to Appearance >> Customize >> Theme Options >> Typography Settings
Look for the “Drop Cap Colour” setting and use the colour selector to find the colour you want. If you have the page open in the preview window that has the drop cap showing, you can see the change happen before you save it.