Application filing

[USCQuestion]

Hello, I would like to know a few things before filing for N400 application.
1. If I file my application online, how is a service center assigned to it? Is it based on my home address or randomly picked?
2. Is it possible to travel outside US after filing the application but before the interview or are there any travel restrictions?
3. Is original birth certificate required during interview process?

Any responses will be highly appreciated.

[N400questions]

I believe the answers are..

1. If I file my application online, how is a service center assigned to it? Is it based on my home address or randomly picked?
Ideally it will be the closest office based on your address. However, some Field Offices are in deep trouble and off-loading some cases to "nearby" offices.
If that happens... a 10 minute trip to the local office can become a three hour journey to the off-loaded office.
Seattle are CERTAINLY doing this with off-loading to Yakima and Portland.
Atlanta recently off-loaded some cases to Montgomery Alabama too.

2. Is it possible to travel outside US after filing the application but before the interview or are there any travel restrictions?
Yes you can travel. Life goes on! Obviously don't break the residency and presence rules by being away too long.
Also avoid war zones and similar places.

3. Is original birth certificate required during interview process?
If you have children involved in the process.. yes... you will need the children's birth certificates.
They may get automatic citizenship when you do so USCIS want proof they are your children etc.
I've never seen a Birth Certificate needed for an adult applicant. All nationality questions are answered by your passport.
If you've got yours (birth certificate)... take it. If you've not got yours... maybe you should get one anyway for future reference even if USCIS don't need it.

[USCQuestion]

thank you, does a service center schedule biometrics appointment only or the interview is also held there?

[N400questions]

In my neck of the woods....

The Field Office looks like an upmarket office block and that's where interviews are held.
It's the kind of building where a small to medium sized company may have its corporate offices.
I imagine the furniture is up-market and the floors are carpeted etc.

However, the biometrics locations look like a low-budget location in a run-down retail strip mall.
I guess you only need simple floor-space (low price per square foot) for taking fingerprints.
There's just a couple of machines and a bunch of low-cost chairs on a tile floor posing as a waiting area.

Your area may be different. Take a peek on google street-view. I don't know if there's any national standardization.