how to make a swung dash in macbook pro

On a QWERTY keyboard, it's the key to the left of "1". Use the shift key on that key to get a "~".

adolfo i wrote:

Thanks. However if I follow your advice I get ª. Nos a swung dash.

Then it sounds like you have a Spanish keyboard. As posted earlier, ~ is option ñ then space on that one.

adolfo i wrote:

How to make a swung dash in MacBook Pro

You need to tell us which language keyboard you are using (there are a couple dozen different ones). To get ~ on the Spanish keyboard, for example, it would be Option ñ then space.

For any keyboard, you can see which key does what via

Use the Keyboard Viewer on Mac - Apple Support (BH)

Then, as Tom suggested above, you most likely have chosen a different language in Settings > Keyboards. To further help you, please answer the question he asked above or follow his recommendations to display the Keyboard Viewer.