Step 1: Navigate to Services> Add Service in your WordPress admin sidebar.

Step 2: Create a title, and insert your post content in the editing field.

Step 3: Add Categories from the right side.

Step 4: For a single image, click the first Featured Image Box, select an image and click the Set Featured Image button.

Step 5: Add your post excerpt.

Step 6: Once you are finished, click Publish to save the post.

Here is the screenshot that shows the various areas of the service post page: