Choose node item from list and add to form I have content type 'Machinery' and I need to create the form for users where they can enter their name, email, phone number and to select some node from a list and attach it to form.

The user can select unlimited items and when click on 'Add' to add to form.

In this way, the user has the option to attach some machines to the form and send a request for renting those machines. Email that will be sent from this form needs to contain all fields along with the list of added machines.

Since I need this content type because I'm using it for another page to show the list of available machines, I need to create the form in this way so when I add new machine (node) it's automatically available on this list in the form.

Any idea how I can do this? Is there some way to create form through Views so I can add this list field?

I'm working on Drupal 8.
I'm not sure what kind of form your question is about. You say, you want to e-mail the result, so this is probably a Contact form.

Here you can add a reference field for content and then configure this field for the content type "Machinery". You can set this to unlimited values, so that you can add multiple machines. The default is an autocomplete field. You can change this to a select list in "Manage form display".