It maybe a very confusing question. But I have been contemplating this quite a lot recently.
Ven. Ajahn Chah preached, as the Lord Buddha once said :
One who sees Sankhara and is purged of attachment has happiness. Mind is Sankhara. Body is Sankhara. Sankhara is not us or ours. Thus those who see Sankhara are at peace. They see the mind and body not as 'self' but only as 'Sankhara'. (pg.22, paragraph 3) - Excerpt from 'Being Dharma' By Ven.Ajahn Chah
When I contemplate these deep words, I feel that 'Sankhara' means 'things that are conditioned, impermanent, ever changing and not reliable sources of happiness'.
Wikipedia defines 'Sankhara' as follows:
Saṅkhāra (Pali; Sanskrit saṃskāra) is a term figuring prominently in Buddhism. The word means 'that which has been put together' and 'that which puts together'. In the first (passive) sense, saṅkhāra refers to conditioned phenomena generally but specifically to all mental "dispositions". These are called 'volitional formations' both because they are formed as a result of volition and because they are causes for the arising of future volitional actions. English translations for saṅkhāra in the first sense of the word include 'conditioned things,' 'determinations,' 'fabrications' and 'formations' (or, particularly when referring to mental processes, 'volitional formations'). In the second (active) sense of the word, saṅkhāra refers to that faculty of the mind/brain apparatus (sankhara-khandha) that puts together those formations. https://en.wikipedia.org/wiki/Sa%E1%B9%85kh%C4%81ra
But when we think even deeper, if both mind and body are 'sankhara', then who is the 'being' within our minds, who travels through this eternity of existence? This 'being' that some refer simply (and quite wrongly) as an 'Āthma' or in other ways as 'existence'? If 'Āthma' or 'existence' is Sankhara, then how does it endlessly exist? Sure it changes from one existence to another, but it is endlessly existing , which contradicts the nature of 'Sankhara' itself, making 'our existence' immortal.
It is like a man travelling from house to house. The house breaks down, but the man is eternally travelling. Who is this man, and how is he eternally travelling, is he is also 'Sankhara'? Shouldn't he also end at some point or the other? In this analogy, the man is the 'existence', and the house symbolizes our body and mind.
I know this is very confusing material, but I consider this site a realm filled with knowledgeable beings. I would find myself very happy to find any number of meaningful replies.