"从内容上来说/从形式上来说"用英语怎么说

about the content,
about the form

in the terms of substance
in the terms of form

Formally!

According to the content!

从内容上来说
Based on the content, ...

从形式上来说
Based on the style, ...

in terms of contents,
in terms of form.
或者，
as to the contents,
as to the form也可以的。

个人意见

Speak from inner content

Speak from appearance

这个应该是最地道的说法了