multiple H1

[Daniele]

I would like the source code of my site page not to show the H1 headers of the desktop and mobile at the same time.
I currently use the code
     <div class = "w3-container w3-center w3-margin w3-border-top w3-border-bottom w3-border-gray w3-sand">
         <h1 class = "w3-hide-small w3-hide-medium w3-xxlarge w3-text-gray"> <b> <? = $ title_h1?> </b> </h1>
         <h1 class = "w3-hide-large w3-medium w3-text-gray"> <b> <? = $ title_h1?> </b> </h1>
       </ Div>

how can I do?

[dsonesuk]

Then don't use two! Its seems you want it to show one or the other depending on device size eventhough they are identical? Which Google could frown upon for having duplicate content. Use single h1 with no specific device class so single h1 will show for ALL devices.

[Sherin]

only one h1 tag on a single webpage . however there can be multiple h2 to h6 tags .if you are using  HTML5 you could have only one h1 tag per section.  either you can use p tag on your page and you have to add css on your p tag.