Hello Tia
Sure, if you want to add a shortcode for inner or any contact form then you first you will need to install the contact form 7 plugin and add a new contact form. Once you publish it you will get a shortcode and you will need to use that shortcode in the customizer. copy that shortcode and to paste it go to dashboard > appearance > customize > contact us page> paste the shorcode in the shortcode tab and then publish it you will see the contact page you created in the inner contact page after this.
for testimonial you will need to follow a very simple step just goto dashboard > pages > add new page give it a title for ex: “TESTIMONIALS” or anything you like and in the description you will need to paste this: [TESTIMONIALS] and set the template as default only then click on the publish.
now add the testimonial page in the menu and save it, it will appear in the menu then on your website. If you click on it then you will see all the testimonials there.
After this if you want to add more testimonials then just go to dashboard > testimonials > add new > and enter all the details to create a new testimonial and it publish or update it, it will appear on the testimonial page.
Hope this helped

Thank you for reaching out to us

great!