I understood that imperative is the tu and vous form without the pronoun. Why then is it donne moi ton argent and not donnes moi? Thanks
It's actually a bit more complex than that: only verbs ending in -es in the tu-form drop it in the imperative, otherwise it's kept:
tu manges -> mange !
tu offres -> offre !
tu finis -> finis !
tu fais -> fais !
tu prends -> prends !
tu dors -> dors !
One way to think of it is that it takes the form of the je-form rather than the tu-form.
The two other forms of the imperative are exactly the same as the vous-form and the nous-form.
Four verbs have an irregular imperative based on the subjunctive stem:
savoir -> sache/sachons/sachez
vouloir -> veuille/veuillons/veuillez (but only veuillez is used in practice)
être -> sois/soyons/soyez
avoir -> aie/ayons/ayez
Also note that aller irregularly drops the s in the tu-form: tu vas -> va!
And all verbs that drop the s in the imperative regain it when the pronouns y or en come after: vas-y, manges-en.
As said, you don't have to put an "s" for the "tu" (the second singular person) just because it's a rule.. But have a look to the exceptions!! :)
An other article in english this time : https://www.thoughtco.com/introduction-french-imperative-mood-1368858