Is it possible to get married to a woman who was married before as a Christian? But she has converted on Islam now, but has not yet got a divorce for her Christian marriage. What the process/requirements I might be going through? Is there any way to marry her? I'm a muslim man from bangladesh.
1) She should be legally divorced by the law of the country, in non-Muslim countries.
2) Then she has to wait for the idda period.
Idda period is three menstrual cycles for menstruating women, for pregnant women the idda is after the baby is born. This idda is important so as to clearly understand lineage if she gets pregnant immediately after marriage.
Reference for idda - https://islamqa.info/en/31
One may marry a converted women just like he would marry an ordinary muslim woman. There is no verse or hadith which specifically states any different rules for a woman who was previously non muslim.
As far as her Christian husband is concerned, she is no longer his wife under the law of Islam.