Hi @susananavarro
Here's the [https://kaas.hpcloud.hp.com/pdf-public/pdf_3822522_en-US-1.pdf|maintenance and service guide], taken from this support [https://support.hp.com/us-en/product/setup-user-guides/hp-chromebook-14a-na0000-series/32708668|webpage] for the laptop series.
Go to p.29 (34 of 64 pdf) to view the procedure to remove/replace the battery.
Search online for [https://www.google.com/search?client=firefox-b-d&q=L75783-005|L75783-005] to find battery suppliers that suit you best. (examples only)