Signature in html component in mobile

we have created an html with option to draw on canvas. we used it to draw signature. However the problem is that when we try to sign in mobile, the whole page moves up and down which makes it difficult to sign. It important to say that in the html component we don’t have a scroll bar.i.e. we made it big enough.
Any ideas on how fix the page or disable movement. (we have already tried to add preventDefault() in the html but it didn’t help)