Hi,

By default in Odoo, the currency field is only visible to those users who have access to multiple currencies. If the requirement is to hide the currency from all users “invisible” attribute can be used.

<record id="view_move_form_inherit" model="ir.ui.view">
 <field name="name">view.move.form.inherit</field>
 <field name="model">account.move</field>
 <field name="inherit_id" ref="account.view_move_form"/>
 <field name="arch" type="xml">
 <xpath expr="//field[@name='currency_id']" position="replace">
 <field name="currency_id" groups="base.group_multi_currency"
 attrs="{'readonly': [('posted_before', '=', True)]}"
 invisible="1"/>
 </xpath>
 </field>
</record>

Regards