Yes, most of the everyday branding changes are yours to make from the admin panel, without needing a designer or a developer. Things like uploading your logo, setting your brand colours, changing the homepage banner images, editing the welcome text and updating your company details are normally built in as simple settings. You make the change, save it, and the live site picks it up.
Where it gets less simple is anything structural. Moving the search box to a different part of the page, changing the way search results are laid out, or building a homepage that works completely differently from the template you chose is design work rather than a setting, so that usually needs our team to do it for you. How much of that is included depends on your plan, so it is worth agreeing in advance what counts as a setting you control and what counts as a custom change.
The other honest limit is the booking screens themselves. The search, results and payment pages carry your branding, but their layout is built to work reliably with the suppliers behind them, so they are deliberately less open to editing than your own content pages. That protects your bookings from breaking when something changes on the supplier side.
Before you commit, ask to be shown the branding section of the admin panel on a demo site, and make a short list of the changes you expect to make yourself so we can confirm which of those are settings and which would need our help.