What would be content of recruitment advertisement?

If it is a paid adv. and you need it to be short. Write your company name, vacancies avaliable, location, deadline to apply, mail, website and contact person. 

Purpose of role, and content.

Selection criteria.

Information about the organization – potential candidates.

Location.

Reward package – consider including benefits other than pupillage award,

such as flexible working or exceptional development opportunities.

Application procedure ‐ indicate how candidates can access and submit the

application form and include commitment to make reasonable adjustments

for disabled candidates. Provide the closing date and, where possible, the

expected interview dates.

Again you have explained the issue satisfactorily Mr. Saiful Islam. Thanks you.

A summary of the company with jobs and a brief description of the job and its conditions, e-mail and website advertising in the official newspaper

A very clear picture about the process, timing, requirements as to qualification and experiences, the address to approach and present and a narrative requirement of the job profile also preferable.  Agree with the answer provided by Mr. Saiful Islam Hiron and other professionals.