How words change to different forms ?
Can anyone help me with the way of changing words to different forms such as verb ,adjective ... ?
Or I will be grateful If you introduce a reference .
I know almost nothing about it , and recently I have find it necessary to learn
3 Answers
start here on how the past participle is formed
start here on how the gerundio is formed
After you have read the articles, then ask more specific questions about their usage.
How to use a past participle as as adjective? or How to use the gerundio as a adverb?
How is the pp used in passive voice?, etc.
Hmmm that's a huge subject - do you mean how to change an adjective to fit the noun in gender (masculine or feminine) and number (singular or plural)?
Here's an example - one adjective is 'alto' tall
El chico es alto. The boy is tall.
But if you wanted to say that 'the girl is tall' you would have to change the ending 'o' which is often masculine to fit the girl who is feminine. You do this simply by dropping the 'o' and adding an 'a'.
La chica es alta.
Then if you were talking about two or more people you would also have to make the adjectives plural by adding an s.
Los chicos son altos. The boys are tall.
Las chicas son altas. The girls are tall.
I hope this is a good beginning, Here's a link to Spanish Adjectives 
Nouns, verbs, adverbs, adjectives, prepositions, conjunctions, pronouns, etc. are all different parts of speech and cannot usually be changed from one to another.
Are you talking about conjugating verbs? Using the past participles of verbs as adjectives? Using the verb gerundio as an adverb? Using verb infinitives as nouns? Using lo+adjectives to from nouns?
You are going to have to be more specific. Can you give us some examples of what you are asking about?
A lot of nouns and verbs and adjectives have common roots. Is that what you are asking about?
el gozo (noun) gozar (verb) gozoso(a) (adjective) gozosamente (adverb)
