@OrigamiSkinCare
You can use both of the options you mentioned. One is for email sign up and the other for SMS signup.
But first you need to prepare these things on your end before people can do it.
For the QR code first you need to create the sign up form add it to some specific page on your website, also create a QR code and make sure you link that code to your page that has the sign up form.
And for the text to join you first need to activate Klaviyo SMS options and set what to be the text to join option and then inform you customers about your number and subscription text somehow.. probably it can be on the same flyer as the QR code..