The infinitive form of a verb is relative easily to spot - usually, there is a word TO + the verb form. So here, the infinitive is to quote.
On the other hand, past tense of regular verbs (such as to quote) is formed by adding -ed (or in this case, -d) to the verb. So here, the past tense of the verb is quoted.
Ultimately, we can create nouns from verbs in various ways, by adding various suffixes. Here, that suffix will be -ation. So the noun is quotation.
