Que puedo hacer para practicar en un teléfono HTML??

Answer 1

You can use this app. SoloLearn has html, css, js courses and many more.
And a playground to write and test code.
There you can find a lot of code from others SoloLearner. For inspiration or to learn from.

Have fun.

Answer 2

thank you estefano, I was referring to whether you could encode on a mobile phone, very kind indeed, thank you.