Assalamu alaykum waragmatullahi wabarakatuhu What does this ayah means? "But as for the favor of your Lord, report [it]." (93:11). Is it obligatory to tell others about blessings Allah gave you? -

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

This noble verse enjoins speaking of the blessings of Allah the Almighty, however this matter is desirable, not obligatory. As for the blessing mentioned here, there are three sayings regarding its definition. Ibn Al-'Arabi  said in Ahkam al-Quran:

There are three interpretations regarding what is meant by the saying of Allah (which means): {But as for the favor of your Lord, report [it].} [Quran 93:11]

The first interpretation is that it means “the Prophecy".

The second interpretation is that it is “the Quran”.

The third interpretation is that it means “if you acquire goodness or do good then report it (speak about it) to those people whom you trust and from whom you are safe from their evil and envy,” as reported by Al-Hasan.

It appears from the words of the interpreters of the Quran that speaking of the blessings is subject to two factors:

The first: It should not be spoken of as a way of showing off and being proud.

The second: to speak about it to those people whom you trust and are safe from their evil and envy.

Allah knows best.