By English Tutor, Africa:
Adverbs are used to introduce a statement that contrasts with or seems to contradict something that has been said previously:
Examples of adverbs: However, nevertheless, nonetheless, still, yet, even though, although, though, despite, in spite of, notwithstanding etc… There are quite a few of them and it can be up to you which adverb you choose to use. It has to be appropriate for the sentence you are using it in.
E.g. the “orange peel” is said to be irreversible. However, your skin can improve with targeted exercise and clean eating.
When ever is used for emphasis after how or why; it should be written as a separate word. Thus it is correct to write how ever did you manage?
Rather than however did you manage? (as distinct from other uses of the adverb however, which is always written as one word). With other words such as what, where, and who, the situation is not clear-cut: both two-word and one-word forms (both what ever and whatever, and so on) are well represented, and neither is regarded as particularly more correct than the other.