You're in hiding already? Your best bet would be to stay put and try to hold out until the end of the war. If the situation has gotten to the point that you feel it imperative to hide that means that the Germans are looking for you. That in turn means you are on the list to be deported to a death camp, or if you are very lucky, a labour camp. That means it's at least 1941 if you are in Germany or 1942 elsewhere and that's way too late to try to get out of the country, legally anyway. Emigration is prohibited for Jews by this time.

Your only legal way out is to somehow obtain citizenship in a country that is not at war with Germany. There are some (rogue) diplomats handing out fake passports and fake citizenship papers to Jews in various countries at various times. If you are in Hungary after the German invasion of March 1944 you might become Spanish thanks to diplomat Ángel Sanz Briz or Swedish thanks to Raoul Wallenberg. The Germans will generally respect those papers and not deport you to the camps. If you are in Marseilles in France, try to meet up with Brazilian diplomat Roberto de Castro Brandão or the Turkish Necdet Kent.

Your next best bet, if you are determined to flee rather than hide, is to cross a border illegally.

If you are in France you can try to either sneak into Spain or Switzerland or make for the Italian-occupied southeast of the country, where you will be safe as the Italians will not hand you over to the Germans, though they will put you in a camp. They won't hand you over because a) they are not as genocidally antisemitic as the Germans and b) they resent being told what to do by the Germans. The camp won't be a picnic but you will live.

If you are in Austria or Germany, try Switzerland, you might be one of the lucky 30,000 they let in.

If you are in Poland and it's not yet June 22, 1941, try to cross the border into Soviet-occupied territory. You might be sent to the Far East (of the Soviet Union) and life will be extremely tough but that's a better bet than hanging around. Your chances of survival in Poland are extremely small. Less than 1% of Jews who are stuck in German-occupied Poland will survive the war.