Different width of accordion

https://www.homecredit.ph/betasite/payment/

You can use the adjacent sibling CSS selector:

#item-1 + .accordion-content {
    width: 75%;
}

Its working in content, I try to use that in title, but I have no luck

That will only add a width to the content. If you want to add a width to the titles as well you can just simply use:

#item-1 {
    width: 75%;
}

You’ll need both to set the width for both title and content.