Full instructions for changing or adding a website logo for WordPress can be found on the WordPress website itself. I'm assuming they'll keep those instructions up to date. I'll give you the steps down below as well. You can reach their instructions here:
Let's say you'd like to add a logo. To do so, you'll first need to log into your admin back end. Then, navigate to the Customizer via Appearance > Customize
Once you click that link, you'll see a bunch more. Click the Site Identity
If you already have your logo file created, you can upload it here. If you don't have one yet, you can click the Create Logo
button to visit the Fiverr
website to have someone make one for you. In this case, I'll assume you've already got a logo made. To upload it to your website, click on the Select Logo
button. Then, browse your computer for your logo and upload it.
When you've finished uploading the logo, be sure to click the Publish
button at the top of the Customizer. Doing this will ensure your change has been accepted.
Once the logo it set, you'll notice that two different buttons appear. You can use these to either change (update) your logo or remove it altogether. Also, once you've got a logo set, you can uncheck the Display Site Title and Tagline
option. There's no need for those things anymore.
And that's about it! If you need anymore help, please let me know.