Usually, the procedure for obtaining a Blue Card looks like this:
Find a job in Germany and sign an employment contract with a German employer.
Check your diploma at ANABIN. If your diploma has already been entered there, then proceed to the next point. If your diploma is not there, then you need to order an assessment of your education document from the Central Office for Foreign Education (ZAB - Zentralstelle für ausländisches Bildungswesen).
Collect a package of documents and apply for a national visa at the embassy or consulate of your place of residence.
Upon arrival in Germany, contact the Foreigners' Authority (Ausländerbehörde) and apply for an EU Blue Card.
If at the moment your official place of residence is outside the European Union, then usually you need to contact the German embassy or consulate in your place of residence and apply for a national visa. Further, after entering Germany, you must apply for a Blue Card at the Ausländerbehörde (Ausländerbehörde - Foreigners' Authority) in Germany.
You do not need to obtain a national visa to enter Germany in the following cases:
If you are a citizen of Australia, Israel, Japan, Canada, Republic of Korea, New Zealand, UK and USA, you can enter without a visa and must apply for an EU Blue Card within three months at the Foreigners' Authority at the place of residence. After issuing the EU blue card, you can start employment.
If you have held the EU Blue Card of another EU member state for at least 18 months, you can enter Germany without a visa. An application for an EU Blue Card in Germany must be submitted within one month after entering Germany at the Foreigners' Authority of your place of residence. After issuing the EU Blue Card, you can start employment.
If you already live in Germany with a different residence permit, you can apply for an EU Blue Card at the Foreigners' Authority in your place of residence.