Here you can find the instructions on how to change the Logo.
Method 1. Theme Options
➤ Please follow these steps when setting up logo image.
Open the Magento admin panel and select the Store > Configuration in the sidebar menu.
1. In the panel on the left expand the TemplateMonster section.
2. Then choose Theme Options.
… Also, you can edit a particular store view if you have it. (See Store View option on the tool bar.)
3. Choose the image Logo type.
4. Press the Browse button. Select the image for your Logo and upload it.
5. When complete, tap “Save Config”.
✓ Refresh the Magento cache.
Method 2. Standard
1. Open the Magento admin panel and select Content > Configuration in the side menu.
2. In the list of stores you need click edit at Global-Main Website. Also, you can click edit for a particular store view if you have them.
3. Select the “Header” tab, and upload your logo.
5. Click “Save Config” button.
The logo image file shouls stores under the /images folder of your Magento theme.
✓ Remember to refresh the Magento cache.