Custom form tag / send to body email

hi,
I have a form using CF7.
After submitting, I add my own code add_action (‘wpcf7_before_send_mail’, ‘wpcf7_add_text_to_mail_body’);

Something as a result of various php functions $ test = implode ($ arr_draw);

and I add it to

// set mail property with changed value (s)
$ contact_form-> set_properties (array (‘mail’ => $ mail, ‘mail_2’ => $ mail2));

It works great.
But now I would need the result to be projected not at the end of the email but into the body.
Is there any possibility to create some own “shortcode” into which I would put it over some return .. inserted into the sent form? something like [return-test]

best regard

Mitchi