Sería posible el pago en euro en lugar de en dolar???

The form you need to fill out reports your local tax situation to the IRS (American tax office) via Adobe and allows Adobe to withhold the percentages that the Spanish government and the US government have agreed upon. You need to fill that out, or you will have to pay the American taxes to their full extent. The form guarantees to the US and Spanish tax offices that you pay your dues somewhere.

Accounts created after February 18, 2020 are paid in US dollars.  Currency cannot be changed.

We cannot advise you about your taxes except to say that you must submit a withholding form before you can receive payments.  See below.

https://helpx.adobe.com/stock/contributor/help/Contributor-tax-FAQ.html

Individuals 

If you're a resident of a country that has a tax treaty with the US, you'll typically submit Form W-8 BEN, which enables Contributors residing outside the US to claim treaty benefits to reduce or eliminate US withholding tax.

See W-8 BEN instructions

LLCs, partnerships, and corporations

If you're an LLC, a partnership, or a corporation and your entity isn't organized under US law, you should contact a tax expert in your region to determine which of the following W-8 forms corresponds to your situation, and then submit the appropriate form: 

• W-8BEN-E Form

• W-8ECI Form

• W-8IMY Form

• W-8EXP Form

Spain has a tax treaty with the US.

For further questions, consult your tax expert.