Hi Aruna.
Welcome to AAC.
Via Google.
Unlike the microcontroller, the buffer has a higher tolerance for being loaded down and the buffer will more faithfully output the correct voltages with fast rise times. A level translator is similar to a buffer in that it replicates signals and is tolerant to being loaded down by other stuff.
A buffer is designed to provide a higher fanout than typical devices in a particular logic family. They can also be used to drive non-logic loads like LEDs, etc.
A level translator is designed to interface logic operating at different voltages.
there are different buffers and different level translators . . . even such that share the same functionality --e.g.-- provide fanout or line driving capability or , say , CMOS to TTL translation capability
Generally, in the context of digital circuits....
A buffer maintains the same input and output voltage levels but supports a greater output current load (fan out).
A level translator can change the input voltage level to a different output voltage level.