Hello Daniella! both of them are "preterito imperfecto" but "quería" is indicative and "quisiera" is subjunctive. The indicative mood (modo indicativo) is used when something is real and is happening, had happen or will happen; to make factual statements, ask questions, or express opinions. Quería comer pizza de pepperoni pero la pidieron de queso. (I wanted to eat pepperoni pizza but they asked for cheese) the subjunctive mood is used when it expresses a condition which is doubtful or not factual (a conditional). Expresses a doubt, a wish, regret, request, demand, or proposal. Quisiera comer una pizza de pepperoni. (I would like to eat a pepperoni pizza) Hope I've answered your question, if you have problems or any doubts you can ask me.

Hello Daniella! They mean the same, but "quisiera" is more formal or politically correct. I wish I help you.

the difference is in the verb tenses “quería” is in english the verb in past TO WANT in this case a example: i wanted an apple and “quisiera” example " i would like to speak with you"

Hello Daniela: I think you're asking for which one is better to use in the situation: you are going to say what you want when it's your turn in the window go a bank or in any office. If it's what you are asking, I can tell you that is more used "quisiera" in Latin America and "quería" in Spain. For example, if you need information about transfers in a point of tourism information, in Latin America you would say: "Quisiera información sobre cómo ir al aeropuerto" and in Spain you would say: "Quería información sobre cómo ir al aeropuerto". Regards

Are two different verb tenses, although one or the other is often used to give a certain nuance to a phrase, for example: "Quiero pedirte un favor" (I want to ask you a favor) sounds more direct and sometimes when you try to be a little softer you can say "Quisiera pedirte un favor" (I would like to ask you a favor). Quería - pretérito perfecto - Yo quería comprar una camisa azul pero no había de mi talla. Quisiera - pretérito imperfecto. - Quisiera ayudarte con tu duda pero no sé la respuesta.