Petermann

Add a class in the form field.
Example of use with <a href="https://wordpress.org/plugins/contact-form-7/" rel="ugc">Contact Form 7</a>:
<pre><code>[tel your-phone class:phone placeholder "Phone"]
</code></pre>
Listing of classes available for use.
<pre><code>('span.start, input.start').mff_mask('00/0000');
('span.date, input.date').mff_mask('00/00/0000');
('span.time, input.time').mff_mask('00:00:00');
('span.time2, input.time2').mff_mask('00:00');
('input.date_time').mff_mask('00/00/0000 00:00:00');
('input.date_time2').mff_mask('00/00/0000 00:00');
('input.cep').mff_mask('00000-000', { clearIfNotMatch: true });
('input.zip').mff_mask('00000');
('input.phone, input[name="phonebr"]').mff_mask(PhoneMaskBehavior, nonoOptions);
('input.phone_us').mff_mask('(000) 000-0000');
('input.taxid').mff_mask('00-0000000');
('input.ssn').mff_mask('000-00-0000');
('input.mixed').mff_mask('AAA 000-S0S');
('input.cpf').mff_mask('000.000.000-00', { reverse: true, clearIfNotMatch: true });
('input.cnpj').mff_mask('00.000.000/0000-00', { reverse: true, clearIfNotMatch: true });
('input.money').mff_mask('000.000.000.000.000,00', { reverse: true });
('input.money2').mff_mask('#.##0,00', { reverse: true });
('input.money3').mff_mask('#,##0.00', { reverse: true });
('input.money4').mff_mask('000,000,000,000,000.00', { reverse: true });
('input.money5').mff_mask('#.##0', { reverse: true });
('input.money6').mff_mask('#,##0', { reverse: true });
('input.ip_address').mff_mask('099.099.099.099');
('input.percent').mff_mask('##0,00%', { reverse: true });
('input.percent2').mff_mask('##0.00%', { reverse: true });
('input.percent3').mff_mask('990,0%', { reverse: true });
('input.percent4').mff_mask('990.0%', { reverse: true });
('input.percent5').mff_mask('#,##0%', { reverse: true });
('input.percent6').mff_mask('#.##0%', { reverse: true });
</code></pre>
<a href="https://gist.github.com/petermann/fd1a898e02ca91a0d7231a9f8ee662b4" rel="nofollow ugc">Click here</a> for more details on how to add custom mask.
Optional 
– Added option for the format of the Brazilian phone number, with attribute <code>name</code> equal to <code>phonebr</code>.
<h3>Credits</h3>
<a href="https://github.com/igorescobar/jQuery-Mask-Plugin" rel="nofollow ugc">jQuery Mask Plugin</a>

Masks Form Fields

A plugin to add masks in the form’s fields.

Ruslan Heorhiiev

This plugin adds a new field in which you can set the phone number mask or other to Contact Form 7.
Please notice that Contact Form 7 (version 5.0.3 or latest) must be installed and active.
A new field "mask field" will be added to the Contact Form 7 panel buttons.
Example: [mask* your-tel "mask" "Placeholder"]
Mask definitions: 
"_" – any numeric character.

Contact Form 7 – Phone mask field

This plugin adds a new field in which you can set the phone number mask or other to Contact Form 7.

Masks Form Fields vs Contact Form 7 – Phone mask field