Change the input date format

If the front has the format as you need it, simply change that format in the back to save it as you wish in your database.

Assuming that your field is varchar as you said.

$fecha = new DateTime('2006-12-30');
echo $fecha->format('d-m-Y');

Otherwise it could be like this:

$fecha = new DateTime($_POST['fecha']);
echo $fecha->format('d-m-Y');

The format of inputs of type date is rendered by the browser:

  

The control's UI varies in general from browser to browser; at the   moment support is patchy, see Browser compatibility for further   details In unsupported browsers, the control degrades gracefully to a   simple.

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More info

Therefore, you can not change the format directly if your input is still of type date . If it's not much of a problem, it's best to declare it as type text and use Javascript to format it (with a jQuery datepicker or Bootstrap, for example)

The problem is that in the databases if you use the type date or datetime you will save yyyy-mm-dd if you want to obtain it dd-mm- yyyy you must save it in a field varchar

I see that in the tags you are using php, you can leave the html equal but in php you use the function date:
date('d-m-Y',strtotime(/*nombre de tu campo fecha*/$fecha ));

You can not change the format of input[date] , not at least until today's date. What you can do is give it the format you want before saving the date.

You can achieve this by using momentjs , convert it to a momentjs object and then give it the desired format:

function obtenerFecha(e)
{

  var fecha = moment(e.value);
  console.log("Fecha original:" + e.value);
  console.log("Fecha formateada es: " + fecha.format("DD/MM/YYYY"));
}

<script src="https://momentjs.com/downloads/moment.js"></script>

<input type="date" id="date" onchange="obtenerFecha(this)" />

You must define the pattern you require:

 <input type="date"  pattern="[0-9]{2}-[0-9]{2}-[0-9]{4}" required/>