Can I modify the checkout page without Shopify Plus?

[VitaMeals]

I have the basic plan in shopify, the advisor told me that the only way to change details and squares in the checkout page is to have shopify plus.
my question is:

1) is there any way i could make changes on the checkout page without haveing the shopify plus?
2) if i change to plus and make these changes, will the changes be saved even if i return to the basic plan?

[Taknify]

There is no way to make changes to checkout on basic plan. You have to have Shopify Plus plan. 
No the changes will be lost as I think it will default back to the basic checkout.liquid (on basic this is not provided on backend). 
If this answers your questions, please don't forget to mark this as solution. 
Let me know if you have any further questions.

[Victor]

Hi @VitaMeals,

Only merchants on Shopify Plus can access the checkout.liquid theme file and make code changes to their checkout. If you were to upgrade to Plus, make these changes, and then revert back to a standard plan, the checkout page would revert back to default settings. Please bear in mind that Shopify Plus is our enterprise plan aimed at large stores and it's not as simple as upgrading to Plus before moving back down. You can read more about Shopify Plus on the Help Center.

What sort of changes do you want to make to your checkout? Please note that you can still make some edits within the theme editor and with apps, and you can also use the language editor to change copy and text that appears at checkout even if you are not on Plus.

[VitaMeals]

hello, thnk for the answer!
i wanted to make small edits, but one of them is so critical: i wanted to delete the zipcode square (i only make demostic orders, most people don't know there zipdoe because the country changed all the zipcodes year ago...) 
many customers enters the zipcode and shopify asks them to put "valid number".
i tried to contact to shopify asking them to delete the square or at least accept any value the customer enters, but still didnt receive an answer, this matter really effect the customer experience and make many abandoned carts 😞

[VitaMeals]

hello, thanks for the answer!
i wanted to make small edits, but one of them is so critical: i wanted to delete the zipcode square (i only make demostic orders, most people don't know there zipdoe because the country changed all the zipcodes year ago...) 
many customers enters the zipcode and shopify asks them to put "valid number".
i tried to contact to shopify asking them to delete the square or at least accept any value the customer enters, but still didnt receive an answer, this matter really effect the customer experience and make many abandoned carts .
how cani fix that without paying for plus plan?