Usually companies do give relocation expenses but it depends on their INTERNAL POLICIES. Also, if they have offered you ACCOMODATION then you don't have to worry but if not then sadly you have to search appropriate accomodation for urself and bear all costs on your own [common practice]
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In otherwords, its your own problem where,how & when you find accomodation IF COMPANY IS NOT PROVIDING ACCOMODATION TO U.
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You must ask them b4 coming to Doha or if you know anybody in that company ask them about it. If they have HR department, you can ask them too