Work eligibility is the gate everything else passes through, and it is worth understanding before you send a single application. In most countries you need either a status that carries work rights automatically, such as permanent residence or a spouse or student visa with work permission, or a work visa sponsored by a specific employer. That second route means many employers simply filter out candidates who need sponsorship, so your realistic job pool is smaller than the advertised market.
Key things to check for your target country: whether your visa ties you to one employer or lets you switch, whether there is a labour market test requiring the employer to prove no local could fill the role, any minimum salary thresholds, and whether your profession is regulated and needs local licensing.
Never rely on forum summaries for the final answer. Rules change often, so confirm current requirements on the official immigration website or with the embassy, and be very wary of agents promising guaranteed work permits.