The Capitalist Mode of Production

Karl Marx gives us a useful description of the capitalist mode of production.

“Capitalist production rests on the fact that the productive worker sells
his own labour-power as a commodity to the capitalist, in whose hands it
then functions simply as an element of his productive capital. This
transaction (the sale and purchase of labour-power) does not just
introduce the production process, but implicitly determines its specific character.

The production of a use-value, and even of a commodity
(something that can also be undertaken by independent productive workers)
is here only a means for the production of absolute and relative
surplus-value for the capitalist.

In analyzing the production process, therefore, we saw how the production of absolute and relative surplus-value determines  the duration of the daily labour process, and
the whole social and technical shape of capitalist production. It is within this process that the distinction emerges between the mere maintenance of value (of the constant capital value), the actual reproduction of value advanced (the equivalent for labour-power), and the production of surplus-value, i.e. of value for which the capitalist neither advanced a previous equivalent, nor advances one after the event.

The appropriation of surplus-value (of value over and above the equivalent
of the value advanced by the capitalist), even though it is introduced by
the purchase and sale of labour-power, is an act performed within the
production process itself, and forms an essential moment of the latter."

.”

(Capital Volume II, p461 – Penguin Classics edition)