Whether you can switch from tourist to work status without leaving depends entirely on the country, and it splits roughly into three camps. Some jurisdictions flatly prohibit in-country conversion, requiring you to exit and apply through a consulate, often in your home country. Others allow a change of status from within if you meet conditions and apply before the tourist stay expires. A third group technically allows it but makes the process slow enough that leaving is faster in practice.
Even where conversion is possible, entering as a tourist while already intending to work can be treated as misrepresentation, which is a serious problem if discovered. Timing of the job offer relative to your entry can matter.
Because the stakes include refusals and bans, this is one area where reading the official immigration rules or consulting a licensed immigration adviser for your specific country pays for itself. Your prospective employer's HR or mobility team often knows the local reality better than general forums do.