Hi, I would strongly recommend braces or clear aligners to close that gap to give you the best possible and most aesthetic result.
There are two main methods to close a gap in the front:
1) Place a tooth coloured filling on the sides of the neighbouring teeth to fill up the gap - that would increase the size of the tooth. If you have narrow or smaller front teeth to start with, that could be a good option. If you have normal sized teeth, then placing a filling would make the teeth look too broad and unaesthetic. From the photo, I do feel your front two teeth would look large in proportion to your other teeth if fillings are placed.
2) Orthodontic treatment to close the space - this can be done with a few methods. A simple removable retainer with a metal wire on the outside could close the spaces if the alignment and angulation of the front teeth are relatively straight, and there is sufficient space between the upper and lower teeth. If the front teeth are rotated or tipped, the retainer would not work very well.
Based on the photo, your front two teeth appear to tip or slant outwards at the base of the teeth. Fixed braces or clear aligners would be the best method to close this gap. You may not need to do the full works (i.e. braces for all the teeth, both upper and lower) if the front gap is your only concern. Your orthodontist can advise you on the feasibility of sectional braces, which is placing braces on the front six teeth only, or you could use clear aligners to resolve the gap.
It would be best to seek a consultation from an orthodontist or dentist, and together you could come up with a treatment plan you are most comfortable with.
Hope this helps, all the best!
Dr Geraldine Lee