"Do you need travel support?" Questions on Conference Applications
What you should answer will depend on the conference you're attending and the country it is hosted in. Different conferences will have different amounts of money available for travel support and there is no single set of criteria that is used to determine who is eligible. Often travel support is aimed at students and researchers with a very low budget, for example those from poor countries. It is typically not intended for people who have the budget to attend several conferences, but want to attend more.

So figure out what the eligibility criteria are. If they're not listed on the conference website you can either just fill in "yes" and hope that you are provided with documents that provide further information.

But as is often the case, the simplest way might be to just ask. Send an email to the conference organizers asking what their criteria and intended target audience are for travel support.