Itinerary for 7-9 days in Spain
using public transportation

Welcome to Fodors.

Were you supposed to attach a proposed itinerary or do you expect people here to suggest one?
If the latter you need to do some homework of your own first.
Either way we need more information - who? How Many? When? Must sees? Preferred part of Spain?

Also, have your flights been booked? If so, into which airport? Is it a round-trip flight or multi-city (as in going into one city and flight home from another)?

Is your time stated your time on the ground or does it include flights to/from home or elsewhere?

time of year, budget?

or maybe even an actual question e.g. please can you help with suggestions for an itinerary for.....

Welcome, vinetal! With 7-9 days, you need to get thee to a guide book or read some of the trip reports here and decide what interests you. For me, Madrid with an overnight in Toledo would work in that timeframe using public transportation.

Thanks for your suggestion

Agree, as Spain is actually a very large country and there are many different possibilities of places to see and things to do. It also depends on the time of year. For example Madrid is cold and possibly snowy in the winter while it is very hot in the summer.

Yes ,flights are booked, arriving to Barcelona on February 8, will stay for 2 days Monday and Tuesday ,
how best to plan to see Gaudi and historic center (sagrada familia, - reserve tickets ? Walk to gothic quarter,and La Rambla.
2nd day park Guell - do you need tickets ? Also suggestion of hotel, to be convenient to our sightseeing, and not to brake the bank. Your guidance and help is appreciated .

Wednesday we like to take the train to Madrid, buy train tickets ahead ? In Madrid we staying until Feb.15 Sunday.

Two jet lagged days for Barcelona? Not much! The Gaudi sites alone could easily take 3 days. You can book the ones you want to see in advance or you can stand in line, your call.

No indication the OP is flying in from a different time zone.

Fair enough, so let me restate: Two days for Barcelona? Not much!

The public transport is very good so most places are easy to get to. Train and bus. https://www.tmb.cat/en/home

https://parkguell.barcelona/en tells you everything you need to know

Hotel, well what type? I like to stay in traditional hotel (often on first floor (or second floor if you think the ground floor is the first floor)) but you might prefer more USA type concrete thing. Then again what is the bank you want to break. I tend to pay E100 but you might think E200 is normal. I'd use booking.com to find what I want.

seat61.com on spanish trains.
https://www.renfe.com/es/en the site for information

For us to be able to answer questions you have to give us something to work with

Well, I could help you prepare your itinerary, if you provide the no. of people travelling, adult/kids and what would be your ideal budget.