Grooves or ridges that run from the tip of the nail vertically down to the cuticle are usually a normal nail finding. They do not generally represent an underlying medical problem. It is not clear why they occur, but they are probably genetically determined and, unfortunately there is not much you can do about them.
Sometimes, however, ridges like this can form from treatable causes. For example, fungal infection of the nails may lead to thickening and distortion of the nail, and this may result in ridges forming in the nail sometimes.
Similarly, sometimes if the nail ridges are more irregular and pitted, rather than simple straight up and down, this may be a sign of psoriasis
, which is an condition of the skin and joints which occasionally will cause changes in the nails as well.
I would recommend talking to your primary care doctor
. They will be able to determine if there is something going on that needs to be treatable. Assuming that there is not a treatable cause, then the best thing would be to leave the area alone. You should definitely not pick at or scrape the cuticle, as this may lead to infection or further damage to the nail.