Personalize your Tumblr blog by customizing its look and functionality. Tumblr has a dedicated Edit Appearance screen through which you can modify your existing theme or select an entirely new one. Your Tumblr account also has a Settings panel where you can customize both individual blog and entire account settings.
Customize Your Blog's Appearance
Log in to your Tumblr account, click the Account button at the top of the screen and select Edit Appearance on the drop-down menu.
Click the Edit Theme button next to the Website Theme heading.
Use the fields located under the Appearance Options heading along the left of the screen to customize most major elements of your current theme, including textual and visual elements, or click the Browse Themes button to choose an entirely new theme.
If you elect to choose a new theme, click the All Themes drop-down menu, select a theme category, choose the theme you want to use and then click the Use button.
Make Additional Changes Using Mobile Devices
Although you have to select new themes and make most major appearance changes using a Web browser, you can make some smaller changes to your Tumblr blog's appearance using the official Tumblr app for mobile devices.
Open the Tumblr app on your device, log in to your account and tap the Account icon in the top-right corner.
Select the blog you want to edit.
Tap Edit in the top-right corner.
Customize the elements you want to change. Tap the Edit icon over your profile or header images to select new ones. Touch Accent to change your theme's accent colors or Background to change its background color. Tap Save in the top corner when you're finished.
Customize Account and Blog Settings
In addition to customizing your blog's appearance, Tumblr gives you control over certain elements of your blog's functionality. You can change these settings using the Tumblr website only. They are not accessible via the mobile app.
To edit account settings such as your email address, password, security options and language, log in, click the Account icon in the top-right corner of any Tumblr screen and select Settings. Click the Edit icon next to an item to edit it. Toggle the virtual switches on to enable elements such as two-factor authentication and email-based search.
To edit individual blog settings, click the Account icon in the top corner and select Edit Appearance. Here you can customize elements such as reply settings, submissions, your time zone, whether you want the blog to appear in search results and whether it has adult content. Toggle switches on and off to enable and disable settings. Click Share on Facebook to connect your Tumblr blog to your Facebook account.