Sketch is a Mac-only application that handles graphic design, much like Photoshop. Once the Sketch program is installed on your Mac, you can double-click the appropriate file to open it in Sketch. However, if you're on a Mac and don't have Sketch, you can download the program in its free trial version for 30 days. If you're on a Windows computer or don't want to use Sketch, you can use a browser application to edit a graphic file called Photopea. You can also use the Sketch Viewer if you just want to view the document. This wikiHow teaches you how to open a Sketch file in Sketch, Photopea, or the Sketch Viewer.
Step
Method 1 of 3: Editing a Sketch File on a Windows or Mac Computer

Step 1. Visit
Photopea is a highly recommended program that supports editing Sketch files. The program is free to use, but you can pay a fee of US$9 per month to remove the ads. Photopea can be used through a web browser so it can be accessed on both Mac and Windows computers.

Step 2. Click the File tab
You'll see this tab above the editing space, on the left side of the screen.

Step 3. Click Open
A file browsing window will open.

Step 4. Locate and double-click the Sketch file
The file loading will take a while, but the Sketch file will eventually open in Photopea.
You can edit files just like you would in Photoshop. To learn more, you can search and read articles on how to use Photoshop tools at wikiHow
Method 2 of 3: Using Sketch on a Mac

Step 1. Visit
The Sketch download will start immediately. Otherwise, click the “try again” link at the bottom of the page.

Step 2. Run the installation file
You need to extract the downloaded file, then drag and drop the application file to the “Application” folder to install it.

Step 3. Open Sketch
You can find it in the “Application” folder in the Finder window.

Step 4. Click the File tab
You can see this tab in the upper-left corner of the screen.

Step 5. Click Open
A file browsing window will open.

Step 6. Locate and double-click the file
After that, the file will open in Sketch.
Method 3 of 3: Previewing Sketch Files on PC or Mac Computer

Step 1. Visit
Sketch Web Viewer is a site that allows you to review only Sketch projects.

Step 2. Click the box with the outline
A file browsing window will appear. You can also drag and drop Sketch files into your browser. If you do, you can skip the next step.

Step 3. Locate and double-click the Sketch file
The file will load in the viewer window with information on its elements. For example, if the file has a banner layer above the image, you can see the length and height of the banner box.