I had postmenopausal bleeding after one year. in trans vaginal ultrasound, my endometrial thickness is 10 mm. rest is clear. is it normal?

Probably normal: Based on your age, you are most likely peri menopausal rather than post menopausal. The bleeding may be normal. The endometrial thickness can be up to 16mm in premenopausal and 8mm in post. Therefore, basedn the limited info, your is probably normal. I am sure your md will follow you.

Biopsy. : You should have further evaluation of the lining of your uterus. Either hysteroscopy, sonohysterography, or endometrial sampling.

More hx: I think more history is required before more imaging and invasive procedure. Such as: how often is the bleeding? Are you on any hormone replacements? Etc.