In a chemical reaction, the molecule that takes electrons from other molecules is called an oxidant, which causes the loss of electrons; Whereas, the molecule that contributes electrons is called a reducing agent, which leads to the acquisition of electrons.
Bleach (i.e., sodium hypochlorite, Naoci) is a strong oxidizing agent that can take electrons from dye molecules, change their structure, and make them fade, thus whitening the garment. It's not hard to understand that redox reactions involve electron transfer, but how do you determine the direction and number of electron transfers? This requires an understanding of the oxidation state. The so-called oxidation state refers to the number of electrons that an atom can gain or lose in a redox reaction.
For ionic compounds, the charge number of the ions is equal to their oxidation state. For example, the oxidation state of iron ions formed by the loss of two electrons during the oxidation process is +2, so it has the "will" to acquire two electrons. Simple, isn't it? Even better, this applies to all ions. For example, the oxidation state of sodium ions in table salt (NaCl) is +1 and the oxidation state of chloride ions is -1.
Then a covalent compound like water, the oxidation of the individual atoms.
How is it regulated? In the water molecule, the oxygen atom can be seen as stealing an electron from each of the two hydrogen atoms, filling its outermost electron shell, so its oxidation state can be considered as -2. Many transition metal elements, such as iron, have different oxidation states in different compounds, but can still be transferred by the direction and number of electrons in the common oxidation state of an atom. The oxidation state of an element is usually, but not necessarily, determined by its position in the periodic table.