How to choice my category in yahoo asking?

You cannot select a category before you post your question, but if you include keywords appropriate to the best category, your question may be put there by the algorithm that controls the initial question placement. If your question lands in an inappropriate subcategory when you post it, you can move your question by clicking Edit (pencil icon for mobile)>Edit category just beneath your question, then selecting the category in which it is better suited. 

Once the question posts. Click Edit and then Edit Category. and select the section you want to put it in.

You can't choose a category before you post. Phrase your question carefully, as Y!A uses a 'key words' system to decide the right category for a question. For example, a question about a 'German shepherd' is very likely to go into 'Languages' rather than 'Pets', so be sure the word 'dog' is very obvious in your question.

It is your responsibility as the Asker to check immediately after you've posted, to see what category your question has been placed in. If it's not right, you can always move your own questions, as often as you want.Just click on EDIT and do what it says.

Every category has many sub categories that you need to search out sometimes.

you cant before the question is posted after its posted you can pick it before you post it yahoo will try and guess what category to place it in based on key words used in your question if its not placed correctly you can move it to move it go to your question under the blue edit menu click on edit category then select the new category to put it in then click submit

If you post a question go to your question, click 'Edit' and then select 'Edit Category'. You will see a list of categories and can move it where you want it.

After your question posts, click Edit in a desktop mode and you will see the change category command.