Install Adobe Illustrator in your computer and run the program execution file. Go to “File” menu and create a new web or print file, depending on how you would like your file to be saved after completion. Here, you should first make sure that you are working with the "Essentials" workspace.
Click the “File” and select “Place” from the dropdown menu. You will now have to select the image that you want to add the frame. Select the image and resize it according to your needs. You can do it by using "Selection Tool" and dragging the corners of the picture. You should press and hold "Control + Shift" buttons while you drag the picture. It will keep the picture proportional.
Now, select the "Rectangle Tool" and draw a rectangle at the border of the picture. Adjust the image edges as per your requirements.
From the "Brushes" panel, select the "Borders" and you will see a list of decorative borders. You can use these borders to be a part of your frame. Select the rectangle that you created and then click the border you like. The rectangle will automatically be brushed with the border style you selected, forming a frame at the edges of your picture.
At the “Appearance” panel, double click on the name of the border name at the "Stroke" portion. You can now adjust the thickness of your frame, by setting the “Scale” percentage. For example, if you want your frame to become double in thickness, select %200.
Now, select the colour of the frame from the “Stroke” panel.
Click “File” and select “Save As” and provide the location where you want your file to be saved.