Why we can not apply meta name="viewport"

Question

When we create a webpage of course we will use
<meta name="viewport" content.........
Why in sololearn we can not apply it and the default is
<meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no"/>

Answer 1

//As i know you cannot set your own viewport, It's default by mobile width viewport

Answer 2

://Really your question is confusing one🙄🙄
//You Can apply meta tag on sololearn too

Answer 3

I tried but it didn't work

Answer 4

Do you mean: why isn't the meta viewport tag there by default?
هل تقصد: لماذا لا يوجد meta viewport من الأصل؟

Answer 5

//They are not visible, so it's look like usal page but actually it will be working on background on visible page