Browning leaf edges on older foliage (which the leaves in question appear to be) is a normal part of their old-age deterioration and is usually not concerning. Snake plant is fortunately fairly robust and tolerant of a range of conditions, though it grows best when getting moderate levels of light (not low light, even though they tolerate low lighting for awhile) and being able to dry out some between waterings. Giving them moderately bright light helps the leaves stay more upright, as does avoiding using too much fertilizer (primarily the nitrogen component of fertilizer).

The plant pictured looks pretty good overall, with lots of new/young growth that suggests it's doing well. There's no way for brown leaf edges to heal, but to keep the plant healthy overall, just make sure it's not getting over- or under-watered (with the former being more likely than the latter, given the plant's resilience). When older leaves eventually get too withered or brown-edged, you can cut them off. (No need to trim them at this stage, because they're mostly fine and are still helping to feed the plant.)

Miri