Many people refer to the vertical orientation of a photograph as ‘portrait’, and horizontal as ‘landscape’. While you might think portrait photography is limited to only a portrait-style orientation, it’s actually good practice to take images in both. This will give you a greater chance of success during a shoot, with a greater range of options.
Similarly, you can experiment with Aspect Ratios. 3:2 is the most common format and is provided by 35mm film and standard for most digital cameras, while square or 1x1 is favoured by medium-format-using portrait photographers of old.
Using this square format can encourage you to try new and unexpected compositions and framing, and it may add that extra touch of class or nostalgia that your portraits are lacking. Your aspect ratio may be able to be changed in camera, or you can shoot wide and crop your images to be square in post-production.